The diameter of the flanges shall be at least 1,4 x bore
diameter of the milling tool.
Loosening of the milling tool shall be prevented, e.g. by
using a positive connection between the front flange and
the spindle.
Verification: By checking the relevant drawings,
measurements and inspection of the machine.
An automatic brake shall be provided for all tool spindles
with an un-braked run-down time exceeding 10 s (for
measurement of the un-braked run-down time see Annex
I). The braked run-down time shall not exceed 10 s (for
measurement of the braked run down time see Annex I).
A PL of at least c for the braking function shall be
achieved.
In the case of failure of power supply this run-down time
may be exceeded.
The braking torque shall not be applied directly to the tool
itself or to the tool fixing device.
Where a spring operated mechanical brake is fitted the
last paragraph of EN 60204-1:2006, 9.3.4 does not apply
(see 6.3 y)).
For electrical braking, reverse current injection braking
shall not be used.
As an exception where an electrical brake with electronic
control system is fitted, its control system shall be
designed, as a minimum, in PL=b in accordance with the
requirements of EN ISO 13849-1:2008 and be designed
in category 2 in accordance with the requirements of EN
ISO 13849-1:2008 with the exception that the test rate
requirement in EN ISO 13849-1:2008, 4.5.4 is not
applicable. The safety related part of the control circuit for
braking shall be tested periodically, e.g. by monitoring
braked run down time. The feedback shall come from
either the encoder fitted to the spindle motor or from the
measurement of the residual current in the wires
powering the motor.
The test shall:
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